David Cole, chairman of the Center for Automotive Research in Ann Arbor, said he thinks the UAW agreed to take over responsibility for administering retiree health care benefits in a Voluntary Employee Benefits Administration (VEBA) trust in exchange a for boost in pension payments to the automaker's 269,614 retirees.

But it appears that the details on how GM will fund the VEBA still need to be worked out. GM said in a statement this morning that a "memorandum of understanding to establish an independent retiree health care trust" is part of the new contract.

GM reportedly has agreed to fund 70 percent of its $51 billion in retiree health care liabilities. The UAW would invest that amount to ensure it has enough money to pay for retiree health care.

"It's not clear how they will fund it," Cole said."That's one of the real question marks."